We’re all told to go slap on some sunscreen to protect themselves from the sun, but what if that’s actually causing more harm than protection?
I’ll be going over a the problems and the evidence supporting them when it comes to sunscreen.
Many sunscreens contain aluminum. For that reason alone you should use an alternative to conventional sunscreen. One sunscreen that was analyzed for aluminum concentration, a single application would provide 200mg of aluminum. Another problem is that aluminum is an oxidant. The aluminum in sunscreen might contribute to oxidative damage in the skin, increasing the risk of cancer. I don’t know about you, but anything that increase the risk of cancer is enough for me to dump.
If you though that was bad, wait until we get to the ingredients that actually block UV rays. Sunscreens usually block sunlight in one of two ways: with organic (meaning carbon-based) filters, or with inorganic filters that act as a physical barrier. Let’s start with organic UV filters.
Evidence suggests that organic UV filters are EASILY absorbed into the skin. One of the most commonly used UV filter, oxybenzone, was detected in the urine, blood, and breast milk of people in a study after full-body sunscreen application. It was also found in 96% of urine samples collected in the US during 2003 and 2004. Other UV filters have been detected in 85% of breast milk samples in Switzerland.
Many of these crappy chemicals aren’t even stable when exposed to UV radiation. They can form reactive oxygen species and free radicals. This also cause oxidative damage. PBSA is a UV filter that has been shown damage DNA in human skin cells after exposure to UV rays. This means that the use of chemical sunscreens could increase the risk of cancer. Why would you ever want to take that risk? I know I wouldn’t. To make matters worse, some filters even lose their ability to block UV rays once they penetrate the top few layers of skin, making them useless. As if it isn’t already bad enough, these compounds are also a common cause of photoallergic contact dermatitis.
Lets look past the free radicals for a second. Another concern is toxicity, since these UV filters are absorbed into the bloodstream. One of the primary concerns of that is their potential for endocrine disruption. Several animal and in vitro studies have found negative side effects concerning developmental and reproductive function because of UV filters.
Here’s an example from one of the studies. Oxybenzone (the same chemical found in 96% of urine samples in the US) administered to mice resulted in decreased sperm density and increased numbers of abnormal sperm. Although many animal studies measured toxicity through oral administration, the authors of one review point out that exposure through dermal absorption may pose an even greater toxicity risk because the compounds aren’t digested and metabolized by the liver before entering systemic circulation.
Inorganic UV Filters
Inorganic filters are usually nanoparticles of either zinc oxide or titanium dioxide. Like organic filters, both types of nanoparticles can form reactive oxygen species and free radicals when exposed to UV light. Again, in vitro studies show that they can damage human cells. Even worse, one study using human immune cells found that levels of reactive oxygen species generated by nanoparticles in combination with UVA light was not higher than the level of reactive oxygen species generated by UVA light alone, so nanoparticles might not contribute significantly to oxidative damage caused by sun exposure.
Either way, these effects are only relevant if nanoparticles can actually penetrate the top layer of skin and reach living cells. Their ability to do so is controversial, but most evidence indicates that they can’t. Even in skin that is sunburnt or affected by psoriasis, zinc and titanium nanoparticles only penetrate the top layer of skin (the stratum corneum), which is made up of dead cells, and don’t reach living cells.
That said, sunburn did result in deeper penetration into the stratum corneum, and I certainly wouldn’t dismiss the possibility that repeated application of sunscreen to freshly shaven skin that is then exposed to sunlight for long periods of time (in other words, normal summertime behavior) could cause nanoparticles to make their way into living tissue. And remember those PEG compounds that can enhance the absorption of other chemicals in personal care products? They’re found in sunscreens, too.
Based on the evidence so far, I’d play it safe and avoid all commercial sunscreens. I’d rather just stay out of the sun when it’s the strongest an limit my exposure when I need to be out.
Alternatives to sunscreen
To be honest, the best way to protect yourself from the sun is to avoid being in it long enough to get hurt. Building a baseline tan as soon as it starts to get warm enough to bare the weather is a very effective method. As soon as the weather is in the 60’s, I’m outside sunbathing minimally. By the time summer comes by, my tan is strong enough to withstand enough sun for me to not have to worry for the rest of the summer.
Wearing long sleeves and having beach umbrellas when you can is a great way to avoid damage as well. Protect yourself with shade and cover. Do it the old fashioned way!